Effects of sitting, supine, and prone postures on nasal patency in individuals with obstructive sleep apnea syndrome

BACKGROUND: Studies have found that in healthy individuals without nasal disease, changes in posture cause an increase in nasal resistance, especially in the prone posture. Many patients with obstructive sleep apnea syndrome (OSAS) sleep in a prone posture, but no studies have examined the effect of this change in posture on nasal resistance in patients with OSAS. Therefore, we conducted this study to investigate this posture-related physical phenomenon in individuals with OSAS.

METHODS: We evaluated the nasal patency of 29 patients diagnosed with OSAS using the visual analog scale (VAS), acoustic rhinometry, and video-endoscopy in the sitting, supine, and prone postures.

RESULTS: In the OSAS group, both supine and prone postures significantly influenced subjective nasal blockage and led to a notable reduction in the minimal cross-sectional area (mCSA) as determined by acoustic rhinometry, compared to the sitting posture. The prone posture exhibited a more pronounced effect than the supine posture. Endoscopic evaluations further revealed increased hypertrophy of the inferior turbinate in the supine posture for the right nasal passage and the prone posture for the left. However, no significant differences were observed between the prone and supine postures.

CONCLUSION: In OSAS patients, nasal resistance significantly increased in supine and prone postures compared to sitting, with the prone posture showing a greater effect. Clinicians should consider a patient's habitual sleep posture and the effects of postural changes when assessing OSAS severity and devising treatment plans.